The present disclosure is generally directed to flow controllers that restrict, block, divert or otherwise control the flow of fluid through a liquid flow path or switch the flow of fluid between a first and second liquid flow path. More specifically, the present disclosure is directed to easy to use and ergonomical flow controllers that are more easily manipulated than current frangible sealing devices or clamps.
Fluid flow controllers are commonly used in the medical field to control fluid flow within (typically) disposable, flexible tubing and container sets used to process biological fluids (i.e., processing sets) such as, but not limited to, blood. Flow controllers may be used to initially restrict and subsequently establish fluid flow between parts of the processing set. Alternatively, flow controllers may be used to restrict or block, sometimes irreversibly, flow through an initially open flow path. In certain biological fluid processing applications, flow controllers may be used to switch (e.g., toggle) between open flow and restricted flow positions.
One of the most common types of fluid flow controllers used in the medical field is the frangible or breakable sealing device. Frangible sealing devices are often used in the medical field to initially restrict and subsequently establish fluid flow within a processing set. Current day frangible sealing devices typically include a breakable cannula within the hollow interior of a housing, disposed within the flow path of the tubing or container. The cannula blocks the flow of fluid through the hollow interior and thus prevents liquid flow through the flow path. When required, fluid flow is established by bending the housing such that the cannula within the housing breaks and ceases to block the flow of fluid within the housing and the processing set, generally. Examples of prior art frangible sealing devices (sometimes referred to herein simply as “frangibles”) are provided in, for example, U.S. Pat. Nos. 4,899,903 and 5,330,464, both of which are hereby incorporated by reference in their entireties.
Current frangibles provide a one time seal in that fluid flow cannot be restricted again through the frangible once the frangible has been broken. Frangibles must be resistant to easy breakage during shipment and handling, which often means that significant force must be exerted by the user to break the frangible during use. Current day frangibles have a fairly uniform housing cross section and uniform thickness of the housing wall.
Thus, at least one of the drawbacks of current day frangibles is that they are often difficult to bend at the appropriate location and even more difficult to break. Another drawback of current day frangibles is that they do not provide adequate gripping surfaces for the user. In addition, difficult to break frangibles can also result in incomplete breakage of the internal cannula and, therefore, a less than adequately open flow path (as the broken piece may still partially occlude the fluid path, thereby restricting fluid flow). This, in turn, may result in hemolysis of the blood cells or have other deleterious effects on the blood or other biological fluid. Accordingly, there is a need for easy to use flow controllers that avoid the drawbacks of current day frangibles.